野生稻DNA导入水稻后代的SSR检测分析

以宁夏地区水稻主栽品种‘宁粳16号’、‘宁粳23号’为受体,普通野生稻(Oryza rufipogon,2n=2x=24, AA)为供体,利用花粉管通道导人法与茎注射法相结合的导入方法,将普通野生稻DNA导入宁夏水稻栽培品种, 对筛选出的21份形态、农艺性状典型变异的D2代材料及其对照利用SSR分子标记进行分子鉴定,结果表明,有 17份变异材料扩增出野生稻特有的DNA片段,而2个对照均不能扩增出野生稻特异的DNA片段,证明这些材料就是野生稻DNA片段导入的后代。另外有些材料出现受体DNA条带的减少,可能是由于野生稻DNA片段整合到水稻基因组中该引物结合位点或附近,原有的结合位点破坏而造成的。     

利用SSR技术分析我国16种甜玉米的遗传特性

利用SSR分子标记研究16个甜玉米品种的遗传变异。从200对SSR引物中筛选出10对具有稳定多态性的引物,它们在供试材料中共检测出254个位点,每对引物检测位点5-38个,平均为25.4个,得出的平均多态性信息量为0.920 8;据此进行了聚类分析,将16个品种分为3大类。研究表明,SSR分子标记技术可以用于品种间的遗传分析,方便杂交育种品种的选择。     

宁夏主要水稻品种（系）Rf 1基因位点多态性分析

以宁夏49份主要水稻品种(系)为实验材料,对各材料在Rf-1基因位点的功能标记进行分析和基因序列对比,并对各材料在不同位点的差异进行聚类分析,以明确Rf-1位点的规律和特证,为不育系或恢复系的转育及其分子标记选用、杂交组合配置和杂种优势的利用提供理论参考。结果表明:(1)有11个品种(系)为Rf1a/Rf1a基因型,占宁夏主要水稻品种(系)的22%。(2)Rf1b基因位点检测结果有17个点的碱基发生突变,其中2459、2283、2059、1694、2205、1784、2315位点在各品种(系)中突变的频率较高,1576、1881、1970(1985)位点突变的频率低。(3)突变主要是碱基的替换,其位点多,品种(系)间变化大;插入突变位点相对少,只有极少数品种(系)发生插入突变;各品种(系)平均有8个突变位点。(4)聚类分析发现,宁夏主要水稻品种(系)可以划分为三类,每类对应了不同时期的主要品种(系),从第一类群体到第三类群体品种(系)间的差异增加,多样性更丰富,但平均每个品种突变点由9个下降到7个。     

应用PCR进行水稻染色体末端区域作图

利用RAPD引物介寻的不对称复性温度PCR的方法（RM－PCR）,发展了一种基于端粒重复序列的新型分子标记。并在一个籼粳杂交来源（窄叶青8号×京系17）的水稻双单倍体群体中进行了端粒重复相关顺序的遗传定位。在23个定位位点中,有12个定位在水稻8个染色体臂的最远端,并将所在染色体分别向外延长了7．7～22．6cM。其中有些可能是定位在亚端粒区。有5个位点被定位在着丝粒区,另外6个位点定位于染色体内其他区域。     

辽宁省近15年的部分水稻主栽品种的简单重复序列(SSR)多态性分析

应用简单重复序列(SSR)标记方法对辽宁省近15年的14个大面积种植的水稻品种进行遗传多样性分析的结果表明,17对引物共产生43个位点,其中多态性位点17个,平均每对SSR引物检测到2.53个,占位点总数的39.53%。用Nei’s公式计算水稻品种间的遗传距离,并以算术平均非加权聚类(UPGMA)法进行聚类分析并结合系谱分析结果表明,辽宁省近15年的水稻主栽品种遗传多样性不够丰富,多数品种间的亲缘关系较近,欲进一步提高产量还需拓宽遗传基础。     

白桦AFLP遗传连锁图谱的构建

以80个中国白桦(Betula platyphylla Suk)×欧洲白桦(Betula pendula Roth)的F1个体为作图群体, 利用扩增片段长度多态性(Amplified fragment length polymorphism, AFLP)标记, 按照拟测交作图策略, 分别构建了中国白桦和欧洲白桦的分子标记遗传连锁图谱。从64对AFLP引物组合中筛选出34对多态性丰富的引物组合, 这些入选的引物组合在分离群体中共检测到451个多态性位点。χ2检验结果表明, 有362个位点符合1∶1分离(拟测交分离位点), 41个位点符合3∶1分离, 20个位点符合1∶3分离, 28个位点属偏分离位点。在符合拟测交分离的位点中, 201个位点来自中国白桦, 161个位点来自欧洲白桦。利用2点连锁分析, 来自中国白桦的201个标记构成了14个连锁群(4个以上标记), 10个三连体和14个连锁对, 45个为非连锁位点, 连锁标记覆盖的总图距为1 296.1 cM, 平均图距15.5 cM。而来自欧洲白桦的161个标记构成了17个不同的连锁群(4个以上标记), 8个三连体和4个连锁对, 15个为非连锁位点, 连锁标记覆盖的总图距为1 035.8 cM, 平均图距12 cM。     

水稻茎秆解剖结构与抗倒伏能力关系的研究

利用石蜡切片法研究了抗倒伏水稻品种南粳44、武运粳7号与不抗倒伏水稻品系宁7412基部茎秆解剖结构及其与水稻抗倒伏能力的关系.结果表明:抗倒伏水稻品种南粳44和武运粳7号基部节间的维管束数目较多,维管束鞘较厚,细胞层数较多,细胞排列紧密、体积较小;而不抗倒伏水稻品系宁7412基部节间的维管束数目偏少,维管束鞘较薄,细胞层数较少,细胞体积大.从解剖结构还可看出,南粳44和武运粳7号茎秆内的贮藏物质明显多于宁7412.这些茎秆解剖结构的差异可用于区分不同水稻品种(系)的抗倒性强弱,可以作为抗倒伏水稻品种的选育指标和筛选依据,为水稻抗倒伏品种的选育提供了理论依据.     

基于SSR标记的宁夏水稻遗传多样性分析

选择自上世纪80年代以来的59份宁夏水稻种质,利用分布于12条染色体的82对SSR引物进行遗传多样性和遗传相似性分析。共检测到339个等位基因,品种间不同位点等位基因数目2~19个,平均4.13个。Nei基因多样性指数变幅为0.0333~0.9164,平均为0.4394。按种质释放或审定年代,55份水稻分为3组分析,随着年代的增加,等位基因数和遗传多样性指数均呈增大趋势,且3群体间等位基因数和多样性指数差异均达极显著水平（P<0.001）。UPGMA聚类分析表明,参试59份水稻种质在遗传相似系数0.78水平上聚为5大类,其中第Ⅰ类为1份香稻种质;第Ⅱ、Ⅳ类均为3份种质;第Ⅲ类有5份种质,与吉林水稻相似;绝大多数品种被聚为第Ⅴ类,占参试材料数的79.7％。对比宁夏水稻选育品种系谱,大多数种质具有宁夏骨干亲本红旗12、京引39、东方红2号、京引59等的血缘,种质间亲缘关系较近。虽然近年来宁夏水稻的遗传多样性有增加的趋势,但遗传基础狭窄,参试种质的相似系数在0.75以上,最高达0.97。应继续加大力度引进和创新亲本材料,拓宽宁夏水稻的遗传基础。     

利用SRAP标记分析中国主栽孔雀草品种的遗传多样性

为了解中国主栽孔雀草品种的遗传背景,采用相关序列扩增多态性(SRAP)分子标记分析了28份孔雀草材料的遗传多样性。14对SRAP引物组合共获得271个位点,其中多态位点151个,占55.72%。每对引物可扩增出14~24条DNA片段,平均19.4条。引物的多态信息含量PIC值在0.693~0.967之间,平均为0.909;每个材料得到的多态性条带比例介于38.78%与51.42%之间,平均46.38%,说明SRAP分子标记可有效鉴别孔雀草种质在分子水平上的遗传变异。品种间的遗传距离值在0.047~0.198之间,平均为0.126;Shannon多样性指数变化于0.178~0.217之间,平均0.201,表明参试的孔雀草材料总体的遗传多样性水平较低。UPGMA聚类后,在遗传距离阈值为0.146处,可将28份材料分为4大类群,与花色表现基本相符,花色可考虑作为孔雀草基于表型分类的主要因子。本研究结果对孔雀草品种鉴定、杂交育种中亲本选配和分子标记辅助选择具有重要意义。     

加工番茄种质资源的SSR分析

为探明加工番茄种质资源间的亲缘关系,利用SSR标记对20份加工番茄品种及育种材料进行了多样性分析。结果表明:从49对SSR引物中筛选出12对扩增稳定、条带清晰且多态性丰富的引物进行分析,共获得43个位点,多态性位点为37个,多态位点比率86%;供试材料间的遗传相似系数介于0.419~1.000之间,说明加工番茄种质资源间存在一定的遗传差异;通过UPGMA法聚类分析,将20份材料分为3大类群,其中亲缘关系较远的不同类群间及亚类间的种质资源可作为杂交育种的亲本。     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.